Mucolipidosis II. The clinical, radiological and biochemical features in three cases.

We report on the clinical, radiological and biochemical features of mucolipidosis II in three infants. One with subtle phenotypical findings died at 2 weeks of age without a specific diagnosis. A sibling who died at 2 years of age and another infant, presently 3.5 years of age manifest all the characteristic features of mucolipidosis II: extreme psychomotor delay and failure to thrive, coarse facial features, gingival hyperplasia, joint stiffness, inguinal hernia and skin induration. The corneae were normal and there was no mucopolysacchariduria. Radiologically, these infants show changes which are characteristic but not specific for mucolipidosis II. Cytologically, skin fibroblasts from these patients demonstrate the lysosomal inclusions typical of I-Cell Disease. Biochemically, cultured skin fibroblasts show deficient activity of arylsulphatase A and B and hexosaminidase A and B. These acid hydrolases were increased markedly in plasma and in the culture medium of the skin fibroblasts.